Pneumatic annunciator system

ABSTRACT

As a representative embodiment of the present invention, pressure-responsive indicators are coupled to suitable transducers monitoring selected operating conditions of an industrial machine. Pneumatic controls are arranged for providing first pneumatic signals when these operating conditions reach a predetermined value and producing second pneumatic signals should any of the operating conditions vary from its selected range. Other pneumatic controls are uniquely arranged for responding to the second signals to produce a brief third pneumatic signal which is effective to operate only the associated indicator while the other unaffected indicators are positively retained in their safe indicating positions. The indicators of the present invention are adapted to be stacked together and respectively include a number of passages adapted to coincide with the matching passages in the other indicators. One set of these passages in each indicator can be isolated from the other set by orienting the indicator in one position in relation to the other indicators. A second set of these passages is coupled to an alternately-positionable spool in each indicator which is uniquely arranged to select which of the passages in this other set is to be coupled to the pressure-responsive element in that indicator.

United States Patent Harrah 51March 13, 1973 PNEUMATIC ANNUNCIATOR SYSTEM [76] Inventor: Robert S. Harrah, PO. Box 14410,

Houston, Tex. 77021 22 Filed: Nov. 18,1971

[21] Appl. No.: 199,894

Related U.S. Application Data [62] Division of Ser. No. 56,892, July 21, 1970, Pat. No.

[52] U.S. Cl ..ll6/65, l37/557 [51] Int. Cl. ..G08b H04 [58] Field of Search ...1 16/65, 117; 60/105; 137/455, 137/488, 551, 557', 251/289, 318

Primary Examiner-Louis J. Capozi AttorneyDonald Gunn [57] ABSTRACT As a representative embodiment of the present invention, pressure-responsive indicators are coupled to suitable transducers monitoring selected operating conditions of an industrial machine. Pneumatic controls are arranged for providing first pneumatic signals when these operating conditions reach a predetermined value and producing second pneumatic signals should any of the operating conditions vary from its selected range. Other pneumatic controls are uniquely arranged for responding to the second signals to produce a brief third pneumatic signal which is effective to operate only the associated indicator while the other unaffected indicators are positively retained in their safe indicating positions. The indicators of the present invention are adapted to be stacked together and respectively include a number of passages adapted to coincide with the matching passages in the other in dicators. One set of these passages in each indicator can be isolated from the other set by orienting the indicator in one position in relation to the other indicators. A second set of these passages is coupled to an alternately-positionable spool in each indicator which is uniquely arranged to select which of the passages in this other set is to be coupled to the pressure-responsive element in that indicator.

18 Claims, 15 Drawing Figures PATENTEUHAR 1 3 I973 SHEET U 0F 6 k L Q 99 FIG. 20 l FIG. 2C

PNEUMATIC ANNUNCIATOR SYSTEM This application is a divisional application of Ser. N 0. 56,892, filed July 21, 1970 now U.S. Pat. No. 3,651,643, entitled PNEUMATIC ANNUNCIATOR SYSTEM, by the same inventor.

Various pneumatic systems have, of course, been proposed heretofore for controlling the operation of unattendedindustrial machines such as compressors, engines, or the like. In general, these systems typically include a plurality of electro-pneumatic controls any one of which, upon sensing an unsafe or undesirable operating condition of the machine being monitored, will quickly halt the machine as well as provide a visible signal showing which of these several operating conditions caused the shutdown. To accomplish this, each of these selected operating conditions is monitored by an appropriate condition-responsive monitor or transducer'which is adapted to open a normally-closed venting valve whenever that operating condition departs from a predetermined set point or operating range. Each venting valve is, in turn, connected by a normallypressured conduit or tubing line to a pressure-responsive indicator relay which typically includes a movable member or so-called flag" operatively arranged to present a first visual safe" signal so long as the venting valve remains closed. An unsafe condition will, however, open the associated venting valve so that, once the pressure is reduced in the tubing line, the flag will move to present a second visual signal that this particular condition is no longer correct or safe. Typically,

.these indicator relays will also actuate a pneumatic control while halts the machine upon tripping of any one or more of the several relays.

Those skilled in the art will, of course, appreciate thatthe various indicator relays employed heretofore typically rely upon unbalanced pressure forces acting on a movable piston or diaphragm element to maintain the flags in their normal or safe operating positions as well as to shift the flags to their other positions for signaling a malfunction and actuating the shutdown controls. Generally speaking, these indicator relays employ one or the other of two basic techniques for controlling the position of the movable pressure-responsive member. In one common type of these indicator relays, the pressure-responsive element has equal pressure areas on each side of it. Thus, with this style, so long as the associated transducer-operated venting valve is closed, the visual indicator is maintained in its safe" position by imposing the full supply pressure on one side of the pressure-responsive element and a lesser pressure on the opposite side. Then, when an alarm condition is sensed by the transducer and the control line is vented, the supply pressure is removed from one side of the pressure-responsive element and the lesser pressure, acting on the opposite side, causes the flag to signal the unsafe condition.

n the other hand, with the alternate style of these conventional indicator relays, the pressure-responsive element has unequal effective areas on its opposite sides. Normally, the supply pressure is imposed on both sides of the element; and opening of the venting valve will then function to vent the supply pressure from the larger side of the pressure-responsive element, allowing the supply pressure on the smaller side to shift the flag to its alternate position.

Regardless of which of these two styles are utilized in a multiple-control annunciator system, those skilled in the art will appreciate that although these indicator relays of the prior art will usually halt the monitored machine, it is not at all uncommon for the visual indicator or flag to fail to signal the origin of the malfunction responsible for the shutdown. This will, of course, require extensive and needless trouble-shooting just to determine the underlying cause for the shutdown of the machine. For example, in the typical annunciator systems employed heretofore, many of these prior indicator relays include one or more valves for controlling the pneumatic pressures involved in the shutdown system. As a result, should a venting valve which is opened by an improper operating condition be at the end of a particularly-long tubing line, there will be a significant lapse of time between the opening of this transducer-operated valve and the complete venting of the system. Accordingly, as the pressure begins to slowly drop in the control line, the system shutdown valves will function and vent the pneumatic supply before the control line has vented. Should this occur, the pressure still remaining in the long control line will unwittingly reset the indicator relay to again display a safe signal and thereby remove any indication as to which operating condition caused the shutdown of the machine.

To avoid this undesirable resetting of the indicator relays, various arrangements have been typically employed heretofore for retarding, the venting of the supplylines so that the longer control lines will hopefully be vented before the supply pressure is significantly diminished. This, however, requires that the entire pneumatic system be painstakingly balanced to prevent the loss of indication. This balancing must be done judiciously, however, or another equally undesirable result will be introduced. If the supply to the indicators is maintained for'too long a time after the initial sensor has vented, then an indicator relay monitoring a condition dependent upon the continued operation or movement of the machine will trip without valid reason as the machine begins slowing and before the supply pressure has been removed from the system. As a result, when the machine finally comes 'to a halt,

although the properly-tripped indicator will correctly to provide various new and improved pneumatic annunciator systems for reliably indicating only those malfunctioning operating conditions actually causing the shutdown of the'machine being monitored without also falsely actuating other indicators monitoring different and unaffected operating conditions.

It is a further object of the present invention to provide new and improved pneumatic indicators which are especially adapted for use with the new and improved pneumatic annunciator systems of the present invention.

It is still another object of the present invention to provide new and improved pneumatic indicators which are uniquely arranged for compact mounting on control panels with only a minimum of piping connections being required to adapt the indicators in a given group for respectively monitoring selected conditions.

These and other objects of the present invention are attained by arranging a new and improved pneumatic annunciator system having pressure-responsive indicator means operatively coupled to transducer means adapted for monitoring one or more operating conditions of an industrial machine. To enable the system, first means are operatively coupled to the transducer means and adapted for providing first pneumatic signals in response to these operating conditions reaching a predetermined safe or desirable value. Second means are coupled to the transducer means and operatively arranged for providing second pneumatic signals in response to these operating conditions varying from these values. Means responsive to such second pneumatic signals are operatively arranged for imposing a brief, but. positive, third pneumatic signal of limited duration for actuating only the indicator means monitoring the unsafe or undesirable operating conditions to provide a visual indication of a malfunction while the first signals reliably retain the other indicator means in positions indicating those operating conditions which are still within safe operating limits.

The indicators of the present invention are uniquely arranged for cooperative grouping with one or more like indicators. To accomplish this, each indicator has a body in which a pressure-indicator is arranged for movement between first and second indicating positions. A plurality of passages are uniquely arranged in each body so that when two or more indicators are stacked together, the passages will respectively be in communication with one another. By varying the orientation of the bodies in relation to one another as well as by means of a reversible spool member uniquely arranged in each body, any one of these several passages can be selectively coupled to the pressure-responsive indicator in a given body and the other passages isolated from the indicator.

The novel features of the present invention are set forth with particularity in the appended claims. The invention, together with further objects-and advantages thereof,'may be best understood by way of the following description of exemplary apparatus employing the principles of the invention as illustrated in the accompanying drawings, in which:

, FIGS. 1A- 1E schematically depict the sequential operations of a pneumatic system arranged in accordance with the principles of the present invention and including a first set of controls adapted for monitoring oneor more similarly-characterized operating conditions of a typical internal combustion engine;

FIGS. 2A-2D schematically illustrate the sequential operations of a second set of controls for the pneumatic system shown in FIGS. lA-IE while monitoring one or more of a second type of functionally-related operating conditions;

FIG. 3 schematically depicts an alternative control system for use with a group of controls such as shown in FIGS. 2A-2D;

FIGS. 4A-4C depict the sequential operations of a third set of controls for use with the pneumatic system shown in FIGS. lA-IE when a third type of one or more operating conditions are to be monitored;

FIGS. 5 and 6 are cross-sectional views of a preferred pneumatic indicator relay for use with the several systems of the present invention.

Turning now to FIGS. lAlE, a preferred embodiment is depicted of a pneumatic annunciator system 10 arranged in accordance with the present invention, with the various elements thereof being shown in a schematic form for illustrating their various cooperative functions during a typical operating cycle. As best seen in FIGS. 1A, the new and improved annunciator system 10 is basically comprised of a first group 11 of controls for selecting the operational modes of the system, a second group 12 of system-initiating controls, one or more system-controlled elements as at 13, and a third group 14 of controls adapted for initially resetting the various indicator relays employed with the system upon starting of the machine 15 being monitored as well as for actuating only those indicator relays sensing an unsafe condition. To simplify the explanation of the system 10, only a first set of condition-responsive indicator relays, as at 16 and 17, are depicted in FIGS. lA-lE. It will be understood, however, that one or more indicator relays can be included with the system 10 either with or without the relays 16 and 17 for monitoring various types of conditions related to the opera tion of the machine 15 for which the relays 16 and 17 are not suited.

The first group 11 of controls are preferably comprised of a pair of similar or identical manually-actuated valves 18 and 19 respectively having a first normally-open position and a second position which, upon actuation of that valve, will close its inlet port and open its outlet port. An appropriate three-position manual actuator or selector, as at 20, is operatively arranged between the valves 18 and 19 for alternately closing the valves in the two extreme positions of the actuator and opening both of the valves when the actuator is in its depicted neutral position. Accordingly, as seen in FIG. 1A, with the mode selector 20in its neutral or run position, the valves 18 and 19 are in their normallyopen positions. Movement of the actuator 20 to its socalled test position will move the valve 19 to its alternate position but leave the main control valve 1 8 in its normally-open position..Conversely, movement of the actuator 20 to its stop position will shift the main control valve 18 to its venting position without moving the valve 19 from its normally-open position.

A suitable pressure source, such as a typical supply 21 of instrument-quality air, is coupled by a conduit 22 to the inlet port of the main control valve 18, with the common or outlet port of this valve being connected to a supply manifold 23 having four branch conduits 24-27 leading to the second and third groups 12 and 14 of the system controls. Two of these manifold conduits 24 and 26 are respectively coupled to the inlets of similar or identical normally-closed pressure-actuated three-way valves 28 and 29 adapted to vent their outlet ports so long as these valves are not actuated. On the other hand, the other two manifold conduits 25 and 27 are respectively coupled to the inlets of similar or identical normally-open pressure-actuated three-way valves 30 and 31 which, upon their actuation, are adapted to vent their outlet ports. a

The outlet port of the normally-closed valve 28 is coupled by a conduit 32 to the pressure-responsive actuator 33 of the system-controlled element 13 which, if the machine 15 is an internal combustion engine, might be a valve controlling the flow of fuel through a conduit 34 to the machine. Accordingly, as is typical in such situations, the system-controlled element 13 is a normally-closed three-way valve adapted to normally vent the fuel line 34 of the engine 15 and to admit fuel thereto from a suitable source 35 only so long as air of a predetermined pressure is supplied to the pressureresponsive actuator 33.

For reasons that will subsequently be described, a branch conduit 36 is coupled between the outlet port of the normally-closed valve 28 in the second group 12 of system controls to that port of the manually-actuated valve 19 which is normally closed and is opened upon operation of the valve by movement of the manual mode-selector to its test position. A conduit 37 is coupled between the pressure-responsive actuator 38 of the norm ally-closed control valve 28 and the outlet port of the manually-actuated valve 19; and another conduit 39 is coupled between the inlet port of the manual valve and the outlet port of the other normallyclosed valve 29 in the second group 12 of system controls. It will be appreciated, therefore, that so long as the valve 19 is in its depicted position, opening and closing of the control valve 28 is selectively accomplished by correspondingly opening and closing the control valve 29. Similarly, the opening and closing of the system-controlled element 13 is also solely dependent upon the control valve 29.

The outlet of the normally-open valve 30 of the second group 12 of the system controlsis coupled by a conduit 40 and an orifice 41 to one inlet port of a twoway check valve assembly 42 having its other inlet port connected by another orifice 43 to the conduit 32. The common outlet of the check valve assembly 42 is coupled by one conduit 44 to the pressure-responsive actuator 45 of the normally-closed valve 29 and by another conduit 46 to a first manifold 47 having one or more branch conduits, as at 48 and 49, which are respectivelycoupled to each of the several indicator relays 16 and 17. It will be appreciated, therefore, that byvirtue of the orifice 41, the control valve29 will remain closed until this orifice has passed a sufficient volume of air to the pressure-responsive actuator 45 for 1 the pressure appliedthereto to open this control valve. Thus, the delay provided by the orifice 41 will correspondingly delay the opening of the control valve 28 and the operation of the system-controlled element 13.

The pressure-responsive actuator 50 of the normallyopen valve 30 is coupled to the inlet of that valve by means of a selectively-sized orifice, such as a manuallyadjustable needle valve 51, in parallel with a one-way check valve 52 which blocks flow to the pressureresponsive actuator but is adapted to readily open for venting the actuator and a pressure accumulator 53 coupled thereto. It will be recognized, therefore, that admission of compressed air to the pressure-responsive actuator 50 is selectively regulated by the orifice or needle valve 51. Moreover, by virtue of the accumulator 53, the pressure imposed on the pressure-responsive actuator 50 will always be equal to the pressure maintained in the accumulator. Accordingly, since the orifice 51 regulates the rate at which compressed air is admitted to the accumulator 53 and the volume of the accumulator in turn further determines the rate at which the pressure imposed on the actuator 50 increases, the orifice and the accumulator cooperate to delay the closing of the normally-open valve 30 for a selected period of time after air is first supplied to the second group 12 of system controls. On the other hand, upon venting of the supply manifold 23, the check valve 52 will be effective for bypassing the orifice 51 to permit the accumulator 53 to be quickly vented.

The pressure-responsive actuator 54 of the normallyopen valve 31 in the third group 14 of system controls is coupled by a conduit 55 to the outlet of the normallyclosed valve 29 in the second group 12 of system con trols. For reasons that will subsequently be explained, the outlet of the normally-open valve 31 is serially coupled by a conduit 56 to the inlet of another pressure-actuated normally-open valve 57. The pressure-responsive actuator 58 of this valve 57 is coupled to the conduit 56 by a selectively-sized orifice or needle valve 59 which is paralleled with a one-way check valve 60 adapted for venting the actuator upon reduction of pressure at the inlet of thepressure-actuated valve. The outlet of this normally-open valve 57 is coupled by a conduit 61 to a second manifold 62 having one or more branch conduits, as at 63 and 64, which are respectively coupled to each of the indicator relays 16 and 17. It will be appreciated, therefore, that this third group 14 of system controls is effective for supplying a short burst or pulse of compressed air to the manifold 62 which is terminated by the closing of either of the two normally-open valves 31 and 57'. The significance of this function of the third group 14 of system controls will subsequently be explained.

As schematically illustrated in FIG. 1A, the first set of the indicator relays 16 and 17 include new and improved indicator units 65 and 66 respectively having separate bodies 67 and 68 with enclosed chambers 69 and 70 arranged therein in which a piston, as at 71 and 72, is slidably mounted for selective movement back and forth. A suitable visual indicator or flag, as at 73 and '74, is coupled to'each of the pistons 71 and 72 as by a suitable connecting rod, such as at 75 and 76, and operatively arranged so that, upon movement of its associated piston from a retracted position to an extended position, a visual display will be provided to warn that a malfunction has occurred. As depicted, the second inlet conduits 63 and 64 are respectively communicated with the rear of the piston chambers 69 and 70; and the first inlet conduits 48 and 49 are respective ly communicated to the forward portion of the piston chambers by conduits 77 and 78 in series with forwardly-opening check valves 79 and 80. The significance of this arrangement will subsequently be explained.

As is typical, the indicator relays 16 and 17 further include normally-closed, condition-responsive valves, as at 81 and 82, that are respectively coupled by conduits 83 and 84 to the forward portions of the chambers 69 and 70 of the indicator devices 65 and 66. To actuate these valves 81 and 82, each is associated with a suitable condition-sensing actuator, as at 85 and 86, that is operatively arranged to maintain its associated venting valve closed so long as the particular condition being monitored thereby is within a desired operating range. Thus, upon a change of theparticular condition being monitored to what is considered to be an unsafe or undesirable status, the condition-sensing actuator 85 (or 86) will respond and open its respectively-associated venting valve 81 (or 82).

As one example of the utility of the newand improved annunciator system 10 of the present invention, it will be assumed that the indicator relays l6 and 17 are respectively monitoring different parameters functionally related to the operation of the machine and which should not exceed a predetermined limit or range of conditions, but which can safely be either within or below the operating range. For example, where the machine 15 being monitored by the annunciator system 10 is an internal combustion engine or the like, such operating conditions might typically be the engine speed, cylinder-head temperatures, or cooling jacket temperatures. It will, therefore, be appreciated that to monitor conditions such as these, the condition-sensing actuators 85 and 86 are chosen for normally maintaining their respective valves 81 and 82 closed; and that these valves will be opened only in the event that sustained improper operation of the engine 15 causes any one ormore of these various monitored conditions to exceed a safe limit.

To illustrate a typical application of the system 10, assume that the manual selector 20 has just been moved from its stop position to the run" position as depicted in FIG. 1A for initiating the operation of the annunciator system and, as a result, starting the engine 15 being'controlled thereby. Accordingly, movement of the selector 20 to the run position will open the main control valve 18 for admitting compressed air from the pressure source 21 to the inlet manifold 23. The other manual valve 19 will remain in the illustrated position. Since the control valves 28 and 29 in the second group of system controls are at this moment closed, compressed air will initially flow through only the conduits and 27 respectively leading to the second and third groups 12 and 14 of system controls.

Accordingly, oncecompressed air is admitted to the inlet manifold 23, the air will be simultaneously admitted by way of the normally-open valves 30, 31 and 57 to the conduits 40 and 61. However, even though the condition-responsive valves 81 and 82 are closed at this time, the rate at which air is admitted to the first inletconduits 48 and 49 of the indicator relays l6 and 17 will be selectivelyregulated by the orifice 41. Thus, for a finite period of time, the pressure imposed in the forward portions of the piston chambers 69 and 70 will slowly increase from atmospheric pressure to the operating pressure of the air source 21.

On the other hand, since the serially-arranged control valves 31 and 57 in the third group 14 of system controls are both open at the time depicted in FIG. 1A and there is no undue flow restriction between the inlet manifold 23 and the second inlet conduits 63 and 64 of the indicator-relays l6 and 17, the full operating pressure of the air source 21 will be quickly imposed in the rearward portions of the piston chambers 69 and 70. Accordingly, since the pressure differential will be quickly developed across the two pistons 71 and 72, the third group 14 of system controls will function to temporarily shift the visual indicator flags 73 and 74 forwardly to their extended positions as illustrated in FIG. 1A. It will be noted that at this point the second group 12 of system controls are still maintaining the fuel valve 13 closed to preclude the admission of fuel from the fuel supply 35 to the engine 15.

The compressed air passing through the conduit 56 interconnecting the serially-arranged normally-open valves 31 and 57 will, however, gradually impose an increased pressure on the pressure-responsive actuator 58 of the latter valve at a selected rate determined by the orifice 59. Once a sufficient pressure is applied to the actuator 58, the normally-open valve 57 will be closed and the compressed air in the second manifold 62 will be vented as depicted in FIG. 18. Similarly, once a sufficient volume of compressed air has passed the orifice 41 to significantly increase the pressure in the conduit 46 and the first manifold 47, the normallyclosed valve 29 will be opened by the increase of pressure on its actuator 45 and the pistons 71 and 72 will be shifted rearwardly in their respective piston chambers 69 and 70. It will, therefore, be appreciated that the rearward movement of the pistons 71 and 72 will be positively assured since the pressure in the forward por- .tions of the piston chambers 69 and will be approaching that of the air source 21 and the pressure in the rearward portions of the chambers will be decreased to atmospheric pressure once the control valve 57 is closed.

It will also be noted in FIG. 18 that once the control valve 29 opens, the second group 12 of system controls functions to admit compressed air to the pressure-ac,- tuator 38 by way of the manual valve 19 to successively open the control valve 28 and the automatic fuel valve 13. Although the engine 15 is now starting, the normally-open valve 30 of the second group 12 of system controls is still open and will not close until a sufficient quantity of air has passed the controllable orifice 51 to raise the pressure in the accumulator 53 to the actuating pressure of the pressure-responsive actuator 50.

Particular note should be made that the valve 29 must open before the valve 30 closes in order for the fuel valve 13 to be opened and allow the engine 15 to start. Thus, should one of the transducer-actuated I valves 81 and 82 be open by virtue of some malfunction, the valve 30 will close before the valve 29 opens and the engine 15 cannot be started. This interaction between the valves 29 and 30 is, therefore, provided by the cooperative relation of the orifice 51 and accumulator 53 which determines the delay between the opening of the valve 29 and the closing of the valve 30 if no malfunction occurs. Thus, by virtue of this timed delay, a brief flow or pulse of compressed air is provided to the first manifold 47 for a selected time interval which will ordinarily be sufficient to allow the engine 15 to start but which, if either of the valves 81 or 82 are open, will prevent the engine from being started. It will be realized, therefore, that the opening of the valve 29 provides a signal which is indicative that the operating conditions being monitored by the transducers 81 and 82 are each in a safe operating range.

Once, however, the valve 29 opens and the valve 30 closes as shown in FIG. 1C, the double-acting check valve 42 will function as an enabling device to condition the annunciator system 10 for subsequently responding to a malfunction in the engine 15 which will cause an excessive increase in any of the one or more operating conditions being monitored by the new and improved annunciator system of the present invention. The various elements of the annunciator system 10 will, of course, remain in their positions respectively illustrated in FIG. 1C so long as none of the operating conditions being monitored by the condition-responsive valves 81 and 8,2 donot exceed a predetermined level and cause one or more of these valves to open. rdinarily, the various elements of the control system will remain as illustrated until the engine is to be halted routinely. To stop the engine 15, the manual selector is simply moved to its stop" position which closes the main control valve 18 to block further communication between the air source 21 and the inlet manifold 23 and simultaneously vent the entire system to atmosphere.

Turning now to FIG. ID, the annunciator system 10 i is depicted at the moment when the operating condition being monitored by one of the condition-responsive valves, as for example the valve 82 controlling the indicator 66, has exceeded its predetermined limits. When this occurs, the condition-responsive valve 82 will open as illustrated and rapidly .vent the first manifold 47 and the conduit 44 coupled to the pressure-responsive actuator 45 of the valve29 so as to rapidly close this latter control valve. Closing of the valve 29 can, of course, be considered as producing a second signal for indicating that one of the operating conditions being monitored has exceededits selected range.

Reclosing of the control valve 29 will, therefore, simultaneously vent the conduit 55 coupled to the actuator 54 and the conduits 37 and 39 coupled to the actuator 38. Venting of the actuator 38 will, in turn, close thecontrol valve 28 which vents the conduit 32 coupled to the actuator 33 so that the fuel valve 13 is immediately closed. Simultaneously therewith, the control valve 31 is reopened and, as illustrated in FIG. 1D, compressed air is again admitted to the second manifold 62 by way of the still-open control valve 57..

Aswill be appreciated, therefore, with the forward portion of the piston chamber 70 now being at atmospherit is the operating condition being monitored by the indicator relay 17 which was responsible for the shutdown of the engine 15.

It will be noted, however, by comparing FIG. 1D with FIG. 1E that the reapplication of pneumatic pressure in the conduit 56 occasioned by the opening of the valve 31 will soon close the control valve 57 downstream thereof once the orifice 59 has permitted the pressure applied to the pressure-responsive actuator 58 to rise to a sufficient level to operate the latter valve. Thus, the second manifold 62 will be exposed to only a brief surge of pressure upon opening of the valve 31, with thispressure being quickly discontinued upon closing ofthe valve. 57. In other words, the third group 14 of system controls is operative for producing a momentary surge or pulse of compressed air which functions as a third signal for shifting the piston 72 and the visual indicator 74 forwardly. The other piston 71 will, of course, also be'subjected to this momentary pressure pulse or signal and may very likely tend to begin moving forwardly. Yet, since fully-pressured air will still be trapped in the forward portion of the piston chamber 69 between the check valve 79 and the still-closed condition-responsive valve 81, even should the piston 71 shift forwardly the trapped air will be further compressed so that the piston will be positively returned and retained in its normal rearward position once the control valve 31 closes and the manifold 62 is vented as shown in FIG. 1B. It will be recalled, of course, that the compressed air which is effective for retaining the piston 71 in position is provided by the initial signal previously produced.

It will, of course, be appreciated that there are other typical operating conditions which must also be monitored but which are incapable of providing a meaningful control signal until after the engine 15 has been started. For example, with a typical internal combustion engine, engine-driven oil pumps, water-circulation pumps, and the like, are often employed. Although it is important to monitor the discharge pressures of such pumps and guard against excessively-low pressures, these pumps cannot develop their expected operating pressures until the engine 15 is either approaching or has just reached full operating speed. A typical pressure-sensing transducer monitoring conditions such as these will, therefore, falsely signal that a malfunction is occurring untilthe engine 15 has been started. Thus, since the indicator relays 16 and 17 depicted in FIG. IA are critically dependent upon their respective condition-responsive valves 81 and 82 being closed before the engine 15 is started, an alternative arrangement of pneumatic controls :must be provided for those indicator relays which are to monitor those operating conditions which are not satisfied when the engine is first started but which will be satisfied once the engine is operating and is functioning properly.

Accordingly, as depicted in FIG. 2A, an alternative or additional set of controls 87 isprovided for use with one or more indicator relays, as at 88 and 89, respectively including typical condition-responsive valves and 91 which will initially be open and, then subsequently close either as the engine 15' is starting or once the particular operating conditions which they are monitoring respectively reach a predetermined value or range. It will be appreciated, of course, that the controls 87 are to be operatively associated with the annunciator system 10 whether or not the indicator relays l6 and 17 are included. For example, if the indicator relays 16 and 17 are not employed with the additional set of controls 87, the first and second inlet conduits 48, 49, 63 and 64 would not be needed. Onthe other hand, if the indicator relays l6 and 17 are to be associated with the second set of controls 87, the relays will function in the same manner as previously described. The operation of these additional controls 87 will, therefore, not be affected by either the inclusion or the omission of the indicator relays 16 and 17 in the annunciator system 10.

As illustrated in FIG. 2A, the second set of indicator relays 88 and 89 include pneumatic indicator devices, as at 92 and 93, operatively controlled by the condition-responsive valves 90 and 91 which have been appropriately selected for monitoring this second group of operating conditions. It will, of course, be noted that the second indicator devices 92 and 93 are otherwise identical or similar to those previously described and their second inlets are coupled in the same manner to branch conduits 94 and 95 of the second manifold 62. The first inlets of the indicator devices 92 and 93 are,

however, coupled by branch conduits 96 and 97 of a first manifold 98 connected to the outlet port of a twoway check valve 99 that is similar or identical to the first assembly 42 previously described. One inlet of the check valve assembly 99 is connected by a conduit 100 to the outlet of a normally-open control valve 101 having its inlet connected to a branch conduit 10.2 of the first manifold 47. The other inlet of the check valveas sembly 99 is connected by way of a selected orifice 103 and a branch conduit 104 that is coupled to the conduit 40 upstream of the delay orifice 41 (FIG. 1A). The pressure-responsive actuator 105 of the-control valve 101 is coupled by a branch conduit 106 to the conduit 104.

It will be appreciated, therefore, that this additional set of controls 87 will be immediately responsive to the controlled pulses of compressed air supplied to the second manifold 62 by the third group 14 of system controls. On the other hand, as will subsequently be explained, unless the condition-responsive valves 90 and 91 are closed before the cessation of the timed pulse of compressed air supplied to the conduit 104 by the second group 12 of system controls, the annunciator system will halt further operation of the machine 15. Accordingly, the additional controls 87 are depicted in FIG. 2A at the same point in time illustrated in FIG. .IA. The control valves 31 and 57 in the third group 14 of system controls have just functioned as previously described for delivering the brief burst of compressed air to the second manifold 62 to simultaneously move the first and second visual indicators 73, 74, 107 and 108 momentarily outwardly. It will benoted, however,

that the pneumatic pressure in the conduit 104 is funcpressure in the other first manifold 98 cannot increase to any significant level. The second visual indicators 107 and 108 will, of course, remainin their extended positions as depicted in FIG. 2A until the second condition-responsive valves 90 and 91 are closed. The initial open positions of the second condition-responsive- 'It will be recalled that pressure is immediately introduced to the conduit 104 when the engine 15 is started (FIG. 1A) and that this pressure will be maintained only until the valve 30 is closed. Thus, as previously described, this desired timing function is accomplished by selectively arranging the orifice 51 and the accumulator 53 to close the valve 30 at the end of a predetermined time interval so that cessation of the pressure in the conduit 104 will provide a positive signal for enabling further operation of the engine 15 only if the second set of operating conditions have then reached a satisfactory level, This predetermined time interval is,of course, related to what should be the normal time required for these operating conditions to respectively reach a proper level after the engine 15 starts.

Accordingly, as illustrated in FIG. 28, if the condition-responsive valves and 91 close while the second group 12 of system controls are still supplying compressed air to the to the conduit 1 04, the orifice 103 will enable the pressure in the first manifold 98 to rapidly build up for retracting the second indicators 107 and 108 in the same manner as the first indicators 73 and 74. It will be appreciated, of course, that the orifice 103 will prevent excessive loss of compressed air from the conduits 40 and 104 so long as the conditionresponsive valves 90 and 91 are open and the second group 12 of system controls is supplying the timed flow of compressed air to these conduits.

On the other hand, should an operational malfunction hold either of the condition-responsive valves 90 and 91 open longer than anticipated, once the valve 30 closes the pressure in the conduit 104 will be relieved to quickly open the valve 101 and couple the pressured first manifold 47 to the still-vented first manifold 98. It will be appreciated, therefore, from the preceding description as well as from FIG. ID that venting of the pressured first manifold 47 will immediately initiate the shutdown of the engine 15. Thus, depending on the positions of the condition-responsive valves 90 and 91 at-the end of this selected time interval governed by the second group 12 of system controls, the signal provided thereby upon the resulting cessation of pneumatic pressure in the conduit 104 will in one instance permit continued operation of the engine 15 and in the'other in-.

stance immediately terminate the operation of the engine. e 1

. Whenth'e condition-responsive valves 90 and 91 are safely closed before the valve 30 closes to discontinue the signal in th'e conduit 104, the visual indicators 107 and 108 will be retracted; and, once the valve 10] opens as shown in FIG. 2C, the first manifolds 47 and 98 will be coupled to one another by wayof the check valve assembly 99. The additionalcontrols 87 will, of course, remain in their depicted respective positions so long as the operating conditions being monitored by the second indicator relays 88-and 89 are within their specified limits.

It will, of course, be appreciated that opening of one or more of the first set of condition-responsive valves 81 and 82 as depicted in FIGS. 1D and IE will initiate operation of the control system 10 to cause shutdown of the engine 15 Yinv the same manner as already described, When this occurs, so long as the second condition-responsive valves 90 and 91 were closed, the visual indicators 107 and 108 will be retained in their safe" positions. Similarly, opening of either of the second set of condition-responsive valves 90 and 91 will also cause the interconnected manifolds 47 and 98 to be vented to atmosphere as depicted in FIG. 2D. Venting of the first manifolds 47 and 98 will, therefore,

immediately cause shutdown of the engine 15 in the same manner as depicted in FIG. 113. Although it is not necessary to illustrate the actions of the additional set of controls 87 when the annunciator system 10 is func tioning as illustrated in FIG. IE, it should be noted that the visual indicator 108 (as well as the indicators 73 and 74) will be retained in its safe position and the momentary burst of compressed air supplied by the third group 14 of system controls' to the second manifold 62 will move only the other visual indicator 107 forwardly to indicate the source of the malfunction causing the shutdown of the engine 15.

The operating conditions which are to be monitored by the additional set of pneumatic controls 87 must, of course, all reach satisfactory levels within the time interval provided by the orifice 51 and the accumulator 53 of the second group 12 of system controls. It will be appreciated, however, that there may be situations where one or more of such operating conditions may not necessarily reach a satisfactory level by the time that the valve 30 closes.

Accordingly, to permit one or more of such different operating conditions to be reliably monitored by the annunciator system 10, an alternate group 109 of system controls is depicted in FIG. 3 which can be employed for controlling a set of pneumatic controls 110 similar or identical to those depicted in FIGS. 2A-2D and operatively arranged for controlling one or more indicator relays as at 111. Since the respective funcv tions of the alternate group 109 of system controls and the set of controls 110 and 111 are identical to their respective counterparts previously described, it is necessary to point out only that the interval before the cessation of the timed pulse of compressed air supplied to the conduit 112 will be selected in accordance with the particular condition being monitored. This time interval may, of course, be either longer or shorter than that provided by the second group 12 of system controls. Thus, if the branch conduit 113 from the first manifold 47 is not to be communicated with the first manifold 114 until some later time, the controllable orifice 115 as well as the size of the accumulator 116 can be appropriately selected for closing the valve 117 as determined by,the particular situation. Morethan one system ofcontrols, asat 109-111, can, of course, be included in the system 10. In addition to the first and second types of conditions previously described with reference to FIGS. 1A1E and FIGS. 2A--2D, a third type of operating condition is often experienced while operating typical industrial machines. These third conditions are those which may not be satisfied until some undetermined time after the machine is started but which will also be temporarily deficient as that machine is first being started. For example, in a typical installation, there will be instances where a low temperature, a low liquid level, or a low pressure will normally be experienced until sometime after the machine being monitored is started; but, once this condition is satisfied, a subsequent reduction will then endanger the machine. Thus, in distinction to the second type of conditions previously described, these third conditions may either remain unsatisfied for long periods of time or else they will become satisfied at some unpredictable time after the machine has started.

Accordingly, a third set of pneumatic controls 118 is depicted in FIG. 4A for monitoring such conditions. Hereagain, this thirdset of controls 118 is to be used in conjunction with the control system 10 irrespective of whether or not the indicators 16 and 17 are utilized. Similarly, the third set of controls 118 is wholly independent of the second set of controls 87 and can be Used either with or without either this latter system or the pneumatic controls 109-111.

As illustrated in FIG. 4A, the second manifold 62 is also coupled directly to the second inlets of each of one or more indicator relays, as at 119 and 120, such as those previously described. A branch conduit 121 (which will be either coupled to or paralleled with the branch conduit 104 if the second set of controls 87 is being used) is coupled to the conduit 40 between the delay orifice 41 and the control valve 30 (FIG. 1A). It will, of course, be appreciated that the conduit 121 could be alternatively coupled to the conduit 112 (FIG. 3) if the timed interval of the pulse developed by the group 109 of system controls was to be employed. In any event, this branch conduit 121 is, in turn, divided into two other conduits 122 and 123 which are respectively coupled to the inlet of a two-way check valve 124 (similar or identical to those previously described at 42 and 99) as well as to the inlet port of a typical pilotoperated check valve 125. The other inlet of the twoway check valve 124 is coupled by a conduit 126 to the inlet of the control valve 28 controlling the system-controlled element 13 (FIG. 1A).

The outlet of the two-way check valve 124 is coupled to the inlet of a normally-closed control valve 127 having its pressure-responsive actuator 128 coupled by a conduit 129 to the outlet port of the pilot-operated check valve 125. The outlet of the normally-closed control valve 127 is coupled by one conduit 130 to the pressure-responsive actuator 131 of a normally-open control valve 132 and by another conduit 133 and an orifice 134 to one inlet of another two-way check valve 135. The other inlet of this latter check valve assembly 135 is coupled by a conduit 136 to the outlet of the normally-open control valve'132; and the outlet of this check valve assembly is coupled by a first manifold 137 having branch conduits 138 and 139 which are respectively connected to the first inlets of the indicatorrelays 119 and 120. For reasons that will subsequently be explained, a conduit 140 is coupled between the first manifold 137 and the reset or pilot port of the pilotoperated check valve 125. The inlet of the normallyopen valve 132 is coupled to a branch conduit 141 of the first manifold 47.

Accordingly, the third set of controls 118 is depicted in FIG. 4A as it will appear at the same moments respectively illustrated in FIGS. 1A and 2A. Since the second manifold 62 is coupled directly thereto, the brief pulse of compressed air applied thereto will also be effective for initially moving the visual indicators 142 and 143 forwardly. Hereagain, as was the case with the second set of controls 87, since the third conditionresponsive valves 144 and 145 will not be closed for at least a short time interval, the pressure in the first manifold 137 will remain at, or very near to, atmospheric pressure until such time that all of thethird condition-responsive valves have closed when their respective operating conditions have reached their 15 selected operational ranges for the first time. Similarly, since the control valve 132 is temporarily closed, the pressure in the first manifold 47 of the first set of indicator relays 16 and 17 can reach full pressure irrespective of what is happening in either the second or third sets of controls 87 and 118.

Pressure will, however, be applied by way of the conduits 40, 121 and 122 to the left-hand inlet of the twoway check valve 124 and to the inlet of the pilotoperated check valve 125 to retain the control valve 127 open and supply compressed air by way of the orifice 134 to the other two-way check valve 135. This same pneumatic pressurewill also function to maintain the control valve 132 closed. The various elements depicted in FIG. 4A will retain their same positions whenever the system is at the point illustrated in FIG. 18. Similarly, even after the system 10 is functioning as illustrated in FIG. 1C, should the third condition-responsive valves 144 and 145 still be open as shown inFIG. 4A, the various elements of the third set of controls 1 18 will remain in the same positions. These intermediate situations are, therefore, not illustrated. It should be noted, however, that the pilot-operated check valve 125 will initially trap pressure in the conduit 129 to retain the valve 127 open even after the conduit 123 is vented by closing of the valve 30. In this manner, the pressure in the conduit 129 will then be effective for temporarily retaining the valve 127 closed for an indeterminate period of time.

Once, however, the condition-responsive valves 144 and 145 are closed as seen in FIG. 4B, the pressure will rapidly increase in the first manifold 137 to shift the visual indicators 142 and 143 to their safe positions and simultaneously supply a reset signal or pressure pulse to the pilot-operated check valve 125 by way of the conduit 140. It will be appreciated that once the reset signal is applied to the pilot-operated check valve 125, it will open to vent the pressure trapped in the conduit 129 which closes the control valve 127. In this manner, the reset signal to the pilot-operated check valve 125 will be effective for venting the control actuator 131 which, in turn, opens the control valve 132.

As previously described, the shutdown operations of the annunciator system 10 as shown in FIG. 1A and the several sets of controls 87, 110 and 118 are wholly independent of one another. Thus, opening of one or the other of the first or second condition-responsive valves, as at 82 and 90, will cause the annunciator system 10, to halt the engine without affecting the positions of the indicators 142 and 143. Conversely, as illustrated in FIG. 4C, upon opening of. either of the conditionresponsive valves 144 and 145, the third set of controls 118 will halt the engine 15 in the same manner as already described. Thus, as shown in FIG. 4C, should the condition-responsive valve 145 be opened, venting of the first manifold 137 will simultaneously cause venting of the first manifold 47 as depicted in FIG. 1D. This, in turn, will produce the momentary pulse of compressed air through the second manifold 62 to move the appropriate visual indicator 143 outwardly while the check valve 146 and the still-closed condition-responsive valve ,144 cooperate to retain the visual indicator 142 properly positioned. Once the first manifold 47 is vented, the annunicator system 10 will again function as previously described in FIGS. 10 and 1E to shutdown theentire system and halt the engine 15.

Referring again to FIG. 1A, it will be appreciated that a test can be made of the annunciator system 10 (as well as the second and third sets of controls 87, 110, 111 and 118) by momentarily positioning the manual selector 20 in its test position. This will simply supply compressed air through the valve 19 from the conduit 32 (valve 28 initially being open) back to the actuator 38 to retain the valve 28 in its open position so as to keep the fuel valve 13 open irrespective of the sub-v sequent closing of the valve 29 to test the system. Once the valve 19 is in its test" position, any of the condi tion-responsive valves, such as 81, can be manually opened to simulate a malfunction condition. This will cause the appropriate visual indicator, such as 73, to be extended without closing the fuel valve 13. In this manner, a simulated test can be made of the system 10 without halting the engine 15. It will be noted, however, that moving of the manual actuator 20 to the test position will be ineffective until the valve 28 has been opened for the first time.

Turning now to FIGS. 5 and 6, cross-sectional elevation and plan views are shown of a preferred embodiment of a new and improved pneumatic indicating device 150 especially adapted for use with the annunciator system 10 of the present invention and arranged in accordance with the principles of the present invention. The indicating device 150 is uniquely arranged for cooperative grouping with one or more similar or identical devices, as at 151-153, which can be conveniently mounted as a unitary assemblage on a control panel (not shown) with a minimum number of interconnections.

As best seen in FIG. 6, the new and improved indicating device 150 includes a generally-rectangular body 154 of uniform thickness and having opposed upper and lower planar faces to facilitate stacking of the device with the other devices 151-153 in the assemblage. A first elongated bore formed lengthwise through about the middle of the body 154 includes a short reduced forward portion 155 coincidentally aligned with a longer enlarged-diameter rearward porward bore 155 is operatively coupled to a suitable visual indicator or flag 159.

Sealing members, such as O-rings and 161, are,

respectively arranged around the piston 157 and the internal wall of the forward bore 155 for defining a first pressure chamber in the enlarged bore 156 ahead of the piston member. To provide communication with this first pressure chamber, a transverse passage 162 is extended across the body 154 through the forward end of the enlarged bore 156 and preferably terminated by threaded counterbores or ports 163 and 164 formed on the rear face of the device. To close the rear of the enlarged bore 156, a closure member 165 carrying a sealing member 166 is complementally fitted into the rearward end of the bore and retained therein by a cover plate 167 mounted across the rear of the body 154 and secured thereto as by bolts 168 and 169'. To provide communication with the second pressure chamber defined between the sealing members 160 and 166, a vertical passage 170 is formed through the body 154 between its upper and lower faces to intersect the enlarged bore 156 just ahead of the closure member 165.

, A second elongated bore 171 is formed in the body 154 adjacent to one side of the first elongate bore and intersects it through a smaller coincidentallyaligned passage 172 that intersects the transverse passage 162 about midway between the port 163 and the enlarged bore 156. As best seen in FIG. 5, a first pair of vertical passages 173 and 174 are formed through the body 154 between its upper and lower faces and intersect the second bore 171 at longitudinally-spaced intervals. Similarly, a second pair of vertical passages 175 and 176 are formed in the opposite side of the body 154 between its upper and lower faces. For reasons that will subsequently be explained, it will be noted that the passages 173-176 are symmetrically disposed on opposite sides of the enlarged bore 156 and are selectively positioned so that the lateral spacing between each of the four passages and the first bore is equal and the longitudinal spacing between the forward and rearward passages of each pair is equal.

An elongated tubular spool 177 is disposed in the second bore 171 and carries three longitudinallyspaced sealing membersor O-rings 178-180 cooperatively arranged thereon for dividing the elongated bore into forward and rearward enclosed spaces that are isolated from one another and are respectively intersected by the vertical passages 173 and 174. The longitudinal bore 181 throughthe spool 177 is terminated at its opposite ends by semi-spherical counterbores 182 and 183 respectively formed in the forward and rearward end surfaces of the spool. For reasons that will subsequently be explained, a single transverse passage 184 is formed through the spool 177 between the O-rings 179 and 180 and intersects the longitudinal bore 181 through the spool. It will be appreciated from FIG. thatwith the spool 177 in the position illustrated and retained in the second bore 171 by the cover plate 167, the rearward enclosed space will be in communication It will be appreciated from FIG. 6 that the several indicating devices 150-153 are well suited for being stacked together to form a unitary assemblage of any number of the devices. To facilitate their stacking, thin with the vertical passage 173 but will be isolated from I the longitudinal bore 181 through the spool by the 0- rings 178 and 179. Conversely, by virtue of the transverse passage 184, the forward enclosed space between the O-rings 179 and 180 will be in communication with the vertical passage 174 as well as the longitudinal bore 181 through the spool 177. i i

With the spool 17-7 in this position, the vertical passage 173 and its associated rearward enclosed space will be isolated from the longitudinal passage 172 and the transverse passage 162 but the longitudinal bore 181 and the transverse passage 184 in the spool will communicate the vertical passage 174 with the passages 162 and 172 and the enlarged bore 156. To permit flow from the vertical passage 174 to the enlarged bore 156, a typical valve member, such as a ball 185, is operatively disposed in the forward end of the second bore 171 and yieldably biased into seating engagement with the counterbore 183 in the forward end of the spool 177 by a spring 186 that is abutted against a shoulder 187 formed by the junction of the bore 171 and passage 172. In this manner, compressed air can readily flow between the vertical passage 174 and the enlarged bore 156 but the spring-biased ball 185 will prevent flow in the opposite direction.

rectangular plates, as at 188-190, each having five holes therein corresponding to the vertical passages 170 and 173-176 and respectively carrying a sealing member, as at 191, are placed between the opposed faces of each indicating device. To provide a convenient connection with the vertical passages 170 and 173-176, generally-rectangular bodies, as at 192 and 193, are mounted on the top and bottom of the stacked indicating devices -153 and provided with appropriate ports, as at 194-196, for communicating with the passages and 173-176. The complete assemblage of indicating devices 150-153, the plates 188-190, and the upper and lower manifold blocks 192 and 193 are secured together by vertical bolts as at 197 and 198. As best described in a copending application, Ser. No. 777,670, by the present inventor, optical members or lenses, as at 199, are respectively arranged between the forward ends of the spacer plates, as at 188 and 189, for providing a positive visual indication only when the flag 159 is inits forward position immediately to the rear of the lens. To further assure that the flag 159 will remain in its warning position when urged forwardly by the pressure pulse produced upon the occurrence of a malfunction, a spring-biased detent 200 is arranged in the body 154 for cooperation with a reduced portion 201 arranged on the rod 158.

Accordingly, it will be appreciated from the preceding description that when the indicating device 150 is to be used in the annunciator system 10, the first manifold (as at 47 in FIG. 1A) will be coupled to the vertical passage 174 and the second manifold (as at 62 in FIG. 1A) will be coupled to the vertical passage 170. The port 163 can be plugged and the port 164 coupled to the condition-responsive valve (as at 81 in FIG. 1A). The vertical passages 173, and 176 will, or course, be ineffective for purposes of operating the indicator device 150. i

As previously explained with reference to FIGS. lA-lC, the brief pressure pulse initially delivered by way of the manifold'62 to the vertical passage 170 will be effective for temporarily shifting the piston 157 and its associated flag 159 forwardly. Then, once sufficient pressure has builtup in the forward portion of the enlarged bore 156, the piston 157 will be returned to the position illustrated in FIG. 6' to bring the flag 159 to a position indicating a safe operating condition. As previously described with reference to FIGS. lD-1E,venting of the transverse passage 162 will, of course, be effective for initiating the momentary pressure pulse which is delivered by way of the vertical passage 170 to the rear of the piston 157 for driving the piston forwardly. Similarly, if the transverse passage in the indicating device 162 is not vented, the momentary pulse delivered to the vertical passage 170 will not be effective for moving the piston 157 a sufficient distanceforwardly to indicate a malfunction.

It will be recognized, therefore, that by stacking the several indicators 150-153 as shown in FIG. 6, their respective passages 170 will be in alignment with one another to provide an uninterrupted passage from top to bottom of the assemblage which will serve as the common second manifolds, as at 62, with a common port as at 194 and 196. On the other hand, by reversing the elongated spool 177, the longitudinal bore 181 can be selectively placed in communication with either of the vertical passages 173 and 174. The ball member 185 will, of course, be left in its depicted position for seating with either the seat 182 or 183. Moreover, by turning the body 154 over, the passages 173 and 174 will then be placed into communication with the passages 175 and 176 in the adjacent devices 151 and 152. Thus, by reversing the valve spool 177, two additional combinations of interconnection can be readily obtained.

It will be seen, therefore, that by virtue of the alternate positions of the spool 177 as well as the alternate positions of the body 154, any one of the four vertical passages 173-176 can be employed as the first manifold to the indicator device 150 irrespective of the arrangements of the other devices 151-153. Thus, with only the four indicator devices 150-153 in a given stack, each device can be arranged for individual actuation. Similarly, with more than four indicator devices, as at 150, in a given stack, those units sharing a common first manifold (as at 47 in FIG. 1A) will be arranged identically to one another. The remaining units will, of course, be arranged as required to be coupled to the proper first manifold.

Accordingly, it will be appreciated that the new and improved pneumatic annunciator systems of the present invention are uniquely arranged for reliably providing indications of the occurrence of a malfunction of an industrial machine. Moreover by virtue of the cooperative relations of the several signal-producing controls of these annunciator systems, only those indicator relays individually associated with a transducer that actually senses an undesirable operating condition will be tripped so as to accurately designate the source of the malfunction causing the shutdown of the machine being monitored by the new and improved annunciator system. In this manner, false indications will not be presented and there will be no unwarranted resetting of an indicator relay as has been typical heretofore with annunciator systems of the prior art.

Furthermore, by virtue of the unique arrangement of the indicator units of the present invention, a number of these units can be conveniently stacked into a compact group and various connections made thereto. As described, the orientation of each unit with respect to the other units in the stack will provide one set of alternate connection combinations. Moreover, depending upon the position of the selector valve in each unit, another set of alternate connection combinations is provided.

While particular embodiments of the present invention have been shown and described, it is apparent that changes and modifications may be made without departing from this invention in its broader aspects; and, therefore, the aim in the appended claims is to cover all such changes and modifications as fall within the true 7 spirit and scope of this invention.

lclaim:

1. A pneumatic indicator adapted to be joined to another like indicator and comprising: a body having a chamber arranged therein; pressure-responsive indicator means operatively arranged in said chamber and adapted for movement therein between first and second indicating positions in response to pressure signals respectively applied to first and second portions of said chamber; a first passage in said body and communicating with said first portion of said chamber for conducting pressure signals thereto; second and third passages in said body and respectively terminating at an outer surface thereof adapted for placement adjacent to a matching outer surface of the body of a like pneumatic indicator; a fourth passage in said body intersecting said second and third passages and communicating with said second portion of said chamber for conducting pressure signals thereto; and means adapted for selecting which of said second and third passages is to be in communication with said second portion of said chamber and including a spool member adapted for positioning in said fourth passage between said second and third passages in either of two alternate positions therein, seal means adapted for sealing said spool member in relation to said body for isolating said second and third passages from one another and dividing said spool into spaced portions, and passage means in said spool member and adapted for communicating said fourth passage with the exterior of only one of said spaced spool portions to conduct pressure signals to said second portion of said chamber from only that one of said second and third passages then adjacent to said one spaced spool portion.

2. The pneumatic indicator of claim 1 wherein said spool member is adapted to be reversed end for end for selecting which of its said alternate positions it will occupy when said spool member is positioned in said fourth passage.

3. The pneumatic indicator of claim 1 further including check valve means in said passage means adapted for passing pressure signals only from that one of said second and third passages then adjacent to said one spaced spool portion to said second portion of said chamber.

4. The pneumatic indicator of claim 1 wherein said passage means include a bore extending the length of said spool member and terminating at the opposite ends thereof, and a branch bore between said bore and said one spaced spool portion; and further including check valve means adapted for selective cooperation with either of said ends of said spool member for passing pressure signals only from that one of said second and third passages then adjacent to said one spaced spool portion to said second portion of said chamber; and wherein said spool member is adapted to be reversed end for end for selecting which of its said positions it will occupy when said spool member is positioned in said fourth passage.

5. The pneumatic indicator of claim 1 wherein said indicator means include a visual indicator adapted for signifying at least one of said indicating positions of said indicator means.

6. The pneumatic indicator of claim 5 wherein said visual indicator is exterior of said chamber.

7. The pneumatic indicator of claim 5 further including detent means on said body and operatively arranged for retaining said indicator means in said one indicating position upon movement thereto.

8. A pneumatic indicator adapted to be joined to another like indicator and comprising: a body having a chamber arranged therein along a selected axis of said body; pressure;responsive indicator means operatively arranged in said chamber and adapted for movement therein between first and second indicating positions in response to pressure signals respectively applied to first and second portions of said chamber; a first passage in said body and communicating with said first portion of saidchamber for conducting pressure signals thereto; a pair of second passages and a pair of third passages in said body respectively located on opposite sides of said chamber and equally spaced from said axis, said second and third passages respectively terminating at an outer surface of said body adapted for placement adjacent to a matching outer surface of the body of a like pneumatic indicator; a fourth passage in said body intersecting said second passages and communicating with said second portion of said chamber for conducting pressure signals thereto; and means adapted for selecting which one of said second passages is to be in communication with said second portion of said chamber and including a spool member adapted for positioning in said fourth passage between said second passages in either of two alternate positions therein, seal means adapted for sealing said spool member in relation to said body for isolating said second passages from one another and dividing said spool into spaced portions, and passage means in said spool member and adapted for communicating said fourth passage with the exterior of only one of said spaced spool portions to conduct pressure signals to said second portion, of said chamber from only that one of said second passages then adjacent to said one spaced spool portion.

9. The pneumatic indicator of claim 8 wherein the spacing between said pair of second passages is equal to the spacing between said pair of third passages so that either of said pairs will coincide with either of such pairs of passages in a like pneumatic indicator.

10. The pneumatic indicator of claim 9 wherein said second and third passages extend through said body to opposed outer surfaces thereof so that the matching outer surfaces of like pneumatic indicators can be placed adjacent to said opposed outer surfaces and the matching pairs of such passages will coincide with said second and third passages.

11. An assembly of a plurality of pneumatic indicators comprising at least a pair of indicators, each of which is adapted to be connected to a transducer and operated thereby and each of said indicators being comprised of a body having sides thereto; at least two passage means cooperative with said assembly of indicators, said passage means extending through a first body and a second body wherein integrity of communication is achieved by placing said bodies in a side by side relationship; said first indicator being operatively communicated with either one or the other of said passage means; and said second indicator being operatively communicated with either of said passage means.

12. The assembly of pneumatic indicators of claim 11 wherein said first body is constructed and arranged with respect to said second body to permit said bodies to assume a first and a different and second side by side relationship characterized by the fact that said first and second passage means maintain integrity of communications in both side by side relationships.

13. The assembly of claim 12 wherein said first body incorporates a flag means movable between a tripped and an untripped position in response to pressure signals operatively applied thereto; internal passage means within said first body communicating either with said first or second passage means for obtaining therefrom pressure signals for operation of said flag means; and means for selectively limiting communications through said internal passage means to one of said first and second passage means.

14. The assembly of claim 11 wherein said first and second bodies each have opposing faces with openings therein communicating said first and second passage means therethrough, said opening in said first body and in said second body matching one another or juxtapositioning said bodies; and further including sealing gasket means positioned between said opposing faces.

15. The pneumatic indicator assembly of claim 11 further including movable indicator flag means forming a visual signal of the tripped and untripped positions of said indicator; pneumatic responsive means responsive to pressure signals and operably connected with said flag means for moving it to the tripped position; a first manifold pressure source means, connected with said first passage means; a connective means permitting connection of said indicator to a transducer which vents said connective means to a reduced pressure; a source of pneumatic pressure controllably supplied to said pneumatic responsive means for selectively moving said flag means to the tripped. position; valve means communicating said connective means to said first passage means and to said pneumatic responsive means for applying a pressure signal tending to operate said pneumatic responsive means; said valve means, on reduction of pressure from a transducer through said connective means, reducing pressure in said first passage means, and further removing the tendency to operate said pressure responsive means, however said reduction in pressure in said first passage means occurring without regard to operation of said flag means.

16. The invention of claim 15 wherein said source of pneumatic pressure controllably supplied to said pneumatic responsive means forms a pressure pulse after the drop of pressurein said first manifold means, and said pressure pulse is supplied to said pneumatic responsive means to move said flag means to the tripped condition. 1

17. The invention of claim wherein said valve means includes a check valve isolating said first passage means from said connective means and a transducer connected thereto and also from said pneumatic responsive means.

18. The assembly of indicators of claim 11 including a connective block means adapted to permit connection of the transducer thereto, said connective block means permitting connection of the transducer to at least a pair of alternative points on said connective block means and said connective block means operatively communicating the transducer to said body of said indicator. 

1. A pneumatic indicator adapted to be joined to another like indicator and comprising: a body having a chamber arranged therein; pressure-responsive indicator means operatively arranged in said chamber and adapted for movement therein between first and second indicating positions in response to pressure signals respectively applied to first and second portions of said chamber; a first passage in said body and communicating with said first portion of said chamber for conducting pressure signals thereto; second and third passages in said body and respectively terminating at an outer surface thereof adapted for placement adjacent to a matching outer surface of the body of a like pneumatic indicator; a fourth passage in said body intersecting said second and third passages and communicating with said second portion of said chamber for conducting pressure signals thereto; and means adapted for selecting which of said second and third passages is to be in communication with said second portion of said chamber and including a spool member adapted for positioning in said fourth passage between said second and third passages in either of two alternate positions therein, seal means adapted for sealing said spool member in relation to said body for isolaTing said second and third passages from one another and dividing said spool into spaced portions, and passage means in said spool member and adapted for communicating said fourth passage with the exterior of only one of said spaced spool portions to conduct pressure signals to said second portion of said chamber from only that one of said second and third passages then adjacent to said one spaced spool portion.
 1. A pneumatic indicator adapted to be joined to another like indicator and comprising: a body having a chamber arranged therein; pressure-responsive indicator means operatively arranged in said chamber and adapted for movement therein between first and second indicating positions in response to pressure signals respectively applied to first and second portions of said chamber; a first passage in said body and communicating with said first portion of said chamber for conducting pressure signals thereto; second and third passages in said body and respectively terminating at an outer surface thereof adapted for placement adjacent to a matching outer surface of the body of a like pneumatic indicator; a fourth passage in said body intersecting said second and third passages and communicating with said second portion of said chamber for conducting pressure signals thereto; and means adapted for selecting which of said second and third passages is to be in communication with said second portion of said chamber and including a spool member adapted for positioning in said fourth passage between said second and third passages in either of two alternate positions therein, seal means adapted for sealing said spool member in relation to said body for isolaTing said second and third passages from one another and dividing said spool into spaced portions, and passage means in said spool member and adapted for communicating said fourth passage with the exterior of only one of said spaced spool portions to conduct pressure signals to said second portion of said chamber from only that one of said second and third passages then adjacent to said one spaced spool portion.
 2. The pneumatic indicator of claim 1 wherein said spool member is adapted to be reversed end for end for selecting which of its said alternate positions it will occupy when said spool member is positioned in said fourth passage.
 3. The pneumatic indicator of claim 1 further including check valve means in said passage means adapted for passing pressure signals only from that one of said second and third passages then adjacent to said one spaced spool portion to said second portion of said chamber.
 4. The pneumatic indicator of claim 1 wherein said passage means include a bore extending the length of said spool member and terminating at the opposite ends thereof, and a branch bore between said bore and said one spaced spool portion; and further including check valve means adapted for selective cooperation with either of said ends of said spool member for passing pressure signals only from that one of said second and third passages then adjacent to said one spaced spool portion to said second portion of said chamber; and wherein said spool member is adapted to be reversed end for end for selecting which of its said positions it will occupy when said spool member is positioned in said fourth passage.
 5. The pneumatic indicator of claim 1 wherein said indicator means include a visual indicator adapted for signifying at least one of said indicating positions of said indicator means.
 6. The pneumatic indicator of claim 5 wherein said visual indicator is exterior of said chamber.
 7. The pneumatic indicator of claim 5 further including detent means on said body and operatively arranged for retaining said indicator means in said one indicating position upon movement thereto.
 8. A pneumatic indicator adapted to be joined to another like indicator and comprising: a body having a chamber arranged therein along a selected axis of said body; pressure-responsive indicator means operatively arranged in said chamber and adapted for movement therein between first and second indicating positions in response to pressure signals respectively applied to first and second portions of said chamber; a first passage in said body and communicating with said first portion of said chamber for conducting pressure signals thereto; a pair of second passages and a pair of third passages in said body respectively located on opposite sides of said chamber and equally spaced from said axis, said second and third passages respectively terminating at an outer surface of said body adapted for placement adjacent to a matching outer surface of the body of a like pneumatic indicator; a fourth passage in said body intersecting said second passages and communicating with said second portion of said chamber for conducting pressure signals thereto; and means adapted for selecting which one of said second passages is to be in communication with said second portion of said chamber and including a spool member adapted for positioning in said fourth passage between said second passages in either of two alternate positions therein, seal means adapted for sealing said spool member in relation to said body for isolating said second passages from one another and dividing said spool into spaced portions, and passage means in said spool member and adapted for communicating said fourth passage with the exterior of only one of said spaced spool portions to conduct pressure signals to said second portion of said chamber from only that one of said second passages then adjacent to said one spaced spool portion.
 9. The pneumatic indicator of claim 8 wherein the spacing between said pair of second pAssages is equal to the spacing between said pair of third passages so that either of said pairs will coincide with either of such pairs of passages in a like pneumatic indicator.
 10. The pneumatic indicator of claim 9 wherein said second and third passages extend through said body to opposed outer surfaces thereof so that the matching outer surfaces of like pneumatic indicators can be placed adjacent to said opposed outer surfaces and the matching pairs of such passages will coincide with said second and third passages.
 11. An assembly of a plurality of pneumatic indicators comprising at least a pair of indicators, each of which is adapted to be connected to a transducer and operated thereby and each of said indicators being comprised of a body having sides thereto; at least two passage means cooperative with said assembly of indicators, said passage means extending through a first body and a second body wherein integrity of communication is achieved by placing said bodies in a side by side relationship; said first indicator being operatively communicated with either one or the other of said passage means; and said second indicator being operatively communicated with either of said passage means.
 12. The assembly of pneumatic indicators of claim 11 wherein said first body is constructed and arranged with respect to said second body to permit said bodies to assume a first and a different and second side by side relationship characterized by the fact that said first and second passage means maintain integrity of communications in both side by side relationships.
 13. The assembly of claim 12 wherein said first body incorporates a flag means movable between a tripped and an untripped position in response to pressure signals operatively applied thereto; internal passage means within said first body communicating either with said first or second passage means for obtaining therefrom pressure signals for operation of said flag means; and means for selectively limiting communications through said internal passage means to one of said first and second passage means.
 14. The assembly of claim 11 wherein said first and second bodies each have opposing faces with openings therein communicating said first and second passage means therethrough, said opening in said first body and in said second body matching one another or juxtapositioning said bodies; and further including sealing gasket means positioned between said opposing faces.
 15. The pneumatic indicator assembly of claim 11 further including movable indicator flag means forming a visual signal of the tripped and untripped positions of said indicator; pneumatic responsive means responsive to pressure signals and operably connected with said flag means for moving it to the tripped position; a first manifold pressure source means, connected with said first passage means; a connective means permitting connection of said indicator to a transducer which vents said connective means to a reduced pressure; a source of pneumatic pressure controllably supplied to said pneumatic responsive means for selectively moving said flag means to the tripped position; valve means communicating said connective means to said first passage means and to said pneumatic responsive means for applying a pressure signal tending to operate said pneumatic responsive means; said valve means, on reduction of pressure from a transducer through said connective means, reducing pressure in said first passage means, and further removing the tendency to operate said pressure responsive means, however said reduction in pressure in said first passage means occurring without regard to operation of said flag means.
 16. The invention of claim 15 wherein said source of pneumatic pressure controllably supplied to said pneumatic responsive means forms a pressure pulse after the drop of pressure in said first manifold means, and said pressure pulse is supplied to said pneumatic responsive means to move said flag means to the tripped condition.
 17. The invention of claim 15 wherein said valve means includes a check valve isolating said first passage means from said connective means and a transducer connected thereto and also from said pneumatic responsive means. 